KR101143164B1 - Method and apparatus for managing audio input signal in case of photographing moving images in portable termination - Google Patents

Abstract

The present invention relates to a method for processing an audio input signal at the time of shooting a moving picture in a portable terminal.

A method for processing an audio signal input through the microphones when capturing a moving picture in a portable terminal having two omnidirectional microphones spaced from each other according to an embodiment of the present invention includes the steps of: Acquiring information; Selecting any one of a plurality of beam patterns set to have different directivities according to a distance from a specific object based on the distance information; And processing the audio signal input through the microphones based on the selected beam pattern.

Beam pattern, omnidirectional microphone, directivity pattern, delay value

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing audio input signals in a portable terminal,

1 is a configuration diagram of a terminal having an audio signal processing unit according to an embodiment of the present invention;

2 is a configuration diagram of a beam pattern controller according to an embodiment of the present invention;

3 illustrates directivity patterns according to an embodiment of the present invention.

4 is a flowchart illustrating an audio input signal processing process according to an embodiment of the present invention.

The present invention relates to a method and apparatus for processing an audio input signal, and more particularly, to a method and apparatus for processing an audio input signal when capturing a moving picture using a portable terminal.

Mobile Convergence means combining new functions, services, media, etc. with mobile terminals. In recent years, a portable terminal has been developed from a telephone, which is a means for voice communication only, by combining a camera, an MP3 player, and a TV function, thereby providing more convenient additional functions for personal preference as well as voice communication. However, combining the additional functions with a portable terminal having a limitation on the size and the like has resulted in a performance degradation compared with the devices that provided the single function.

On the other hand, according to the demand of the convergence era, the functions of a digital camera (digital camera) and a function of a camcorder capable of video shooting have been added to recent mobile terminals. In general, a camcorder has a relatively small size limitation compared to a portable terminal, and is less restricted by the type, size, and number of microphones. Thus, stereo recording and audio focusing using a stereo microphone or a supergain microphone And there is an advantage that no influence due to the noise due to the modem or other convergence function is almost the same as in the mobile terminal.
However, the moving image shooting function, which is a camcorder function of a portable terminal, is inferior in performance, and the size and noise of the portable terminal are also limited. Accordingly, an attempt has been made to overcome the problem of the function of supporting the motion picture taking of such a mobile terminal, and as a result, a considerable rapid development has been achieved in a short period of time in terms of video such as improvement of the number of pixels displayed on the screen. However, performance improvement is not actively performed in terms of audio. The portable terminal supporting the existing camcorder function mainly performed monaural recording with one omnidirectional or directional microphone, and mainly uses a vocoder-based codec for compression / restoration of voice, Has shown poor performance.

Furthermore, in a portable terminal supporting the existing camcorder function, it is impossible to implement an audio zoom function when recording by using a single omnidirectional microphone. In order to implement the audio zoom function, when the level is simply raised, the level of noise also increases As a result, the noise-to-signal ratio is not improved but rather degraded. In order to overcome this problem, even if a directive microphone is used for recording, the directional microphone needs to be individually tuned for each mobile terminal. In order to create a problem and a directivity pattern that is sensitive to noise, ) Is required. The number of the holes is one of important factors in the design of the portable terminal.

Accordingly, the present invention applies a zoom function to audio when capturing a moving picture in a portable terminal, thereby providing a high-quality audio signal.

In the present invention, a signal-to-noise ratio is increased through an audio zoom function in a portable terminal so that a desired signal can be received more clearly.

The present invention enables a more realistic moving picture photographing through harmonization of a video signal and an audio signal in a portable terminal.

A method for processing an audio signal input through the microphones when capturing a moving picture in a portable terminal having two omnidirectional microphones spaced from each other according to an embodiment of the present invention includes the steps of: Acquiring information; Selecting any one of a plurality of beam patterns set to have different directivities according to a distance from a specific object based on the distance information; And processing the audio signal input through the microphones based on the selected beam pattern.

An apparatus for processing an audio signal input through the microphones at the time of capturing a moving picture in a portable terminal having two omni-directional microphones spaced from each other according to an embodiment of the present invention includes: A video signal processing unit for obtaining distance information; And a controller configured to select one of a plurality of beam patterns set to have different directivities according to a distance from a specific object based on the distance information, And a beam pattern conditioner for processing the signal.

The foregoing is a somewhat broad summary of features and technical advantages of the present invention in order that those skilled in the art will be better able to understand it from the following detailed description of the present invention. Additional features and advantages of the present invention, which form the subject matter of the claims of the invention, in addition to those features and advantages, will be better understood from the following detailed description of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be described with reference to the accompanying drawings. Those skilled in the art will appreciate that the concepts and specific embodiments of the invention described below may be altered or modified in various ways to attain the objects of the invention. It will also be appreciated by those skilled in the art that the concepts and structures equivalent to those disclosed herein are not to depart from the spirit and scope of the broadest form of the invention. It is to be noted that, in the drawings, reference numerals and like components are denoted by the same reference numerals and signs as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a configuration diagram of a terminal having an audio signal processing unit according to an embodiment of the present invention.

Referring to FIG. 1, a radio frequency (RF) unit 105 performs signal transmission and reception in a RF band of a communication terminal. The RF unit 105 includes an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency of the received signal. A modem (MOdulator-DEModulator) 110 encodes and modulates a signal for transmission, and demodulates and decodes the received signal.

The controller 120 controls the overall operation of the terminal. The controller 120 may include the modem 110 and a CODEC (CODEC) decoder 135. However, in the present invention, the codec 135 is configured in the audio signal processor 130. The control unit 120 controls audio signal processing in the audio signal processing unit 130.

The audio signal processor 130 includes an A / D converter 133, a beam pattern controller 134, a codec 135, and a D / A converter 136. An audio signal such as a voice inputted through the two microphones 131 and 132 is applied to the A / D converter 133. The microphones 131 and 132 to be used in the present invention are omnidirectional microphones that are installed to be spaced apart from each other so that audio signals are input with predetermined directionality through the microphones 131 and 132 according to distance information with respect to a subject do. The A / D converter 133 converts an analog value of the audio signal inputted through the microphones 131 and 132 into a digital value. The audio signal having the converted digital value is applied to the beam pattern adjuster 134. The beam pattern adjuster 134 receives distance information from the video signal processor 145 under the control of the controller 120 to select a step of the directivity pattern. The beam pattern adjuster 134 processes the signal applied from the A / D converter 133 according to the selected directivity pattern to direct the signal to the codec 135. A digital audio signal from the modem 110 is also applied to the codec 135. Generally, the codec 135 is divided into a data codec for processing packet data and the like and an audio codec for processing audio signals such as voice. The codec 135 included in the audio signal processing unit 130 of the present invention may process the audio signal and the non-audio signal may be processed by constructing a separate codec. The codec 135 of the audio signal processing unit 130 135 may also process signals other than audio and audio signals. The codec 135 may include a vocoder and an Advanced Audio Coding (AAC). The signals processed by the codec 135 are transmitted to the D / A converter 136 or the modem 110. The D / A converter 136 converts the digital signal input from the codec 135 into an analog signal. A signal converted into an analog value by the D / A converter 136 is reproduced through a speaker 137. The key input unit 165 includes keys for inputting numeric and character information and function keys for setting various functions and outputs a key input signal corresponding to a key input by a user to the control unit 120. [ In addition, the key input unit 165 may include a camera mode execution key, a moving image shooting key, and an end key.

The memory 160 may be composed of a program memory and data memories. The program memory stores a program for controlling the general operation of the portable terminal, and the data memory temporarily stores data generated during the execution of the programs.

The camera unit 140 includes a lens unit (not shown) that can be drawn and drawn, and includes a camera sensor that captures image data and converts the photographed optical signal into an electrical signal. The camera sensor may be implemented as a CCD sensor. The camera sensor and the video signal processing unit 145, which will be described later, may be implemented integrally or separately. The video signal processing unit 145 converts the image signal output from the camera unit 140 into an image signal. The video signal processor 145 may be implemented as a DSP (Digital Signal Processor). A 12-bit RGB signal obtained by digitally converting an analog video signal transmitted from a camera sensor, that is, a serial analog RGB (RED, GREEN, BLUE) signal through an AFE (Analog Front End) The signal processor 145 outputs 8-bit YUV data. Generally, the YUV data is divided into a Y component having luminance and a U component having chrominance. The video signal processing unit 145 provides the audio signal processing unit 130 with distance information with respect to the object to be adjusted so that the object can be photographed optimally under the control of the control unit 120. [

The image processing unit 150 generates screen data for displaying the video signal output from the camera unit 140. The image processing unit 150 processes the video signal output from the camera unit 140 on a frame-by-frame basis and outputs the image data of the frame unit according to the characteristics and size of the display unit 155, which will be described later. In addition, the image processor 150 may include an image codec, compress the image data displayed on the display unit 155 in a predetermined manner, or restore the compressed image data to original image data. have. The image codec may be a Joint Photographic Experts Group codec, a Moving Picture Experts Group codec, a Wavelet codec, or the like. The image processor 150 may output the on-screen display data according to the screen size controlled by the controller 120, assuming that the on-screen display function is provided.

The display unit 155 displays a video signal output from the video processor 150 and displays user data output from the controller 120. In this case, the display unit 155 may include an LCD control unit, a memory capable of storing image data, an LCD display device, and the like. The display unit 155 may be a liquid crystal display (LCD) . When the LCD is implemented by a touch screen method, the display unit 155 may operate as an input unit.

2 is a block diagram of a beam pattern controller 134 according to an embodiment of the present invention. In the present invention using two omnidirectional microphones, one of the audio signals input from two microphones is delayed by a delay value (Delay), and an audio signal is received in a different directional pattern according to the distance from the object. By doing so, an audio signal can be received by using a zoom function similar to a zoom function of a video signal. Here, the zoom function is a function to get closer to the subject or to move away without changing the positional relationship between the subject and the camera. To implement this, the present invention will approach in terms of signal to noise ratio. If simply increasing the gain level to simply pick up a distant subject's signal, the level of the ambient noise also increases, resulting in no change in the signal-to-noise ratio, or rather a degraded performance Because. Accordingly, the present invention proposes a beam pattern conditioner 134 of FIG. 1, wherein when using the beam pattern conditioner 134 to form a directional beam for a desired signal, the level for ambient noise is reduced and relatively collected The level for the desired signal is increased resulting in an increase in the signal-to-noise ratio.

2, the distance d between the right microphone (R) 131 and the left microphone (L) 132 is a distance between two mounted microphones, to be. The delay value is calculated using the d value. A predetermined delay value is added to the audio signal input through the right microphone 131 while passing through the delay unit 210. [ Here, the delay value is obtained by using the distance between the microphones, the sampling rate, and the sound speed. When the step of the directional pattern to be described later is determined according to the distance information to the object provided from the video signal processing section 145, the predetermined other delay value is applied to the inputted audio signal accordingly. The adder 220 adds or subtracts the delayed signal from the right microphone 131 and the audio signal input through the left microphone 132. That is, the summer 220 subtracts the audio signal output from the right microphone 131, which is outputted through the delay unit 210, from the audio signal through the left microphone 132 and outputs the audio signal. Although a delay value is added to the right microphone 131 in the example of the present invention, the delay value may be added to the left microphone 132.

A method of calculating the delay value will be described with reference to an arbitrary numerical value. First, the delay value of the unidirectional pattern shown in FIG. 3 will be described using Equation (1).

Assuming that the distance d between the two microphones is 4.5 cm and the sampling rate R is 44.1 kHz, the sound speed c is a fixed value of 340 m / sec. Therefore, the delay value? 6 samples are obtained. In the present invention, it is assumed that the directivity pattern is set to four levels as shown in FIG. 3, and the delay value (?) 6 samples obtained above is set as a delay value of a uni-directional pattern. A delay value of the super-directional pattern is set by a difference of 2 samples from the determined delay value of the unidirectional pattern. That is, 4 samples is set as the delay value of the high directivity pattern. In the same manner, a delay value of the hyper-directional pattern is set by a difference of 2 samples from the delay value of the high directivity pattern. That is, 2 samples are set as the delay value of the supergain pattern. However, for an omni-directional pattern, the audio signal is input through one of the omnidirectional microphones. That is, in the case of an omnidirectional pattern, it is adjusted by the beam pattern controller to receive the signal with only one omnidirectional microphone without time delay for the incoming signal.

In general, in order to finely control the directivity pattern, a time delay value can be sufficiently secured through a multi-rate signal processing method. The directional pattern steps will be described in detail with reference to FIG.

3 is a diagram illustrating directivity patterns according to an embodiment of the present invention. The present invention classifies the directivity level so that the audio signal is delayed by a delay value corresponding to the received delay value to have a different directivity according to the distance from the subject and receive the signal. As shown in FIG. 3, the present invention classifies the steps of the directivity pattern into four steps in total. However, it goes without saying that the steps of the directivity pattern are changeable and may be changed to be less or more than four steps. The audio signal is delayed by a predetermined delay value according to the selected directivity pattern using the distance information from the video signal processing unit 145 to the object.

Referring to FIG. 3, a first step 310 is a case where a subject is closest to the subject. In this case, an omnidirectional pattern that does not have a directivity is selected and receives an audio signal according to the selection pattern. In the case of the omnidirectional pattern, the audio signal is input only through one of the two omnidirectional microphones. The second step 320 is a case where the distance from the subject is further away than the first step 310, and a hyper-directional pattern is selected. As shown in the drawing, the supergain pattern is a case where two microphone directions toward the subject assumed to be on the front side are more biased than in the case of the one-step omnidirectional pattern. The third step 330 is a direction which is more directional than the second step 320, and a super-directional pattern is selected. In a fourth step 340, a distance from the subject is the farthest away, and a uni-directional pattern is selected to receive the signal in the pattern. The unidirectional pattern receives an audio signal in a state in which the object is completely deviated in the front direction assumed.

4 is a flowchart illustrating an audio input signal processing process according to an embodiment of the present invention.

Referring to FIG. 4, in step 410, the controller 120 checks whether there is an audio signal input through the microphones 131 and 132 in the moving picture shooting mode. If there is an input of the audio signal, the A / D converter 133 converts the analog signal into a digital signal in operation 420. In step 430, the control unit 120 receives the distance information from the video processing signal unit 145 and transmits the distance information to the beam pattern controller 134. In step 440, the beam pattern controller 134 selects one of the four directivity patterns using the distance information with respect to the provided subject. And determines a delay value for delaying the digital signal input from the A / D converter 133 according to the selected pattern. If the directivity pattern of the first stage is selected in step 440, the flow advances to step 452 to perform signal processing according to an omni-directional pattern that does not add a delay value to the signal. If the directivity pattern of the second stage is selected in step 440, the flow advances to step 454 to perform signal processing according to the super directivity pattern that delays the signal by a delay value of the hyper-directional pattern. If the directivity pattern of the third stage is selected in step 440, the flow advances to step 456 to perform signal processing according to a high directivity pattern in which the signal is delayed by a delay value of a super-directional pattern. If the directivity pattern of step 4 is selected in step 440, the flow advances to step 458 to perform signal processing according to a unidirectional pattern in which the signal is delayed by a delay value of a unidirectional pattern. The signal processed by the directivity step is processed by the codec 135 in FIG. 1 in step 460. In step 470, the D / A converter 136 converts the signal processed in step 460 from a digital signal to an analog signal. The signal converted in step 470 is stored in the memory 160 or outputted through the speaker 137 in step 480.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

As described above, since the audio input signal can be processed differently according to the predetermined directional pattern using the distance information with respect to the subject, the desired signal can be received more clearly.

Claims (16)

A method for processing an audio signal input through the microphones when capturing a moving picture in a portable terminal having two omni-directional microphones spaced apart from each other, the method comprising: Obtaining distance information between the portable terminal and a subject; Selecting any one of a plurality of beam patterns set to have different directivities according to a distance from a specific object based on the distance information; And Processing the audio signal input through the microphones based on the selected beam pattern ≪ / RTI > The method according to claim 1, The patterns other than the omnidirectional pattern having a directivity of 0 among the plurality of beam patterns are set so as to delay the audio signal input through any one of the microphones by a predetermined delay value A method for processing an audio input signal. 3. The method of claim 2, Based on the distance between the microphones, the sampling rate, and the sound speed A method for processing an audio input signal. 3. The method of claim 2, The delay value of the unidirectional pattern having the largest directivity among the plurality of beam patterns is set according to the following equation A method for processing an audio input signal. ≪ Equation &

(Where l is the delay value, d is the distance between the microphones, R is the sampling rate, and c is the sound velocity) 5. The method of claim 4, The delay values of the plurality of beam patterns other than the unidirectional pattern are set to have a difference by a set number of samples from a delay value of the unidirectional pattern A method for processing an audio input signal. 3. The method of claim 2, wherein the omni- And the audio signal is set to receive the audio signal through only one of the microphones A method for processing an audio input signal. There is provided an apparatus for processing an audio signal input through the microphones when capturing a moving picture in a portable terminal having two omni-directional microphones spaced apart from each other, A video signal processing unit for obtaining distance information between the portable terminal and a subject; And And selecting one of a plurality of beam patterns set to have different directivities according to a distance from a specific object based on the distance information and outputting the audio signal inputted through the microphones based on the selected beam pattern Lt; / RTI > And an audio input signal processing unit. 8. The apparatus of claim 7, wherein the beam pattern adjuster comprises: For signal processing by the remaining patterns except for the omnidirectional pattern of which the directivity is 0 among the plurality of beam patterns, A delay for delaying an audio signal input through a microphone of one of the microphones by a predetermined delay value; And A subtracter for subtracting an audio signal output through the delay from an audio signal inputted through another one of the microphones and outputting the subtracted audio signal; And an audio input signal processing unit. 9. The method of claim 8, Based on the distance between the microphones, the sampling rate, and the sound speed Audio input signal processing device. 9. The method of claim 8, The delay value of the unidirectional pattern having the largest directivity among the plurality of beam patterns is set according to the following equation Audio input signal processing device. ≪ Equation &

(Where l is the delay value, d is the distance between the microphones, R is the sampling rate, and c is the sound velocity) 11. The method of claim 10, The delay values of the plurality of beam patterns other than the unidirectional pattern are set to have a difference by a set number of samples from a delay value of the unidirectional pattern Audio input signal processing device. The apparatus of claim 8, wherein the beam pattern adjuster comprises: Wherein when the omnidirectional pattern is selected from among the plurality of beam patterns, the audio signal is received through only one of the microphones Audio input signal processing device. delete delete delete delete

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